Trial neuro stimulator with lead diagnostics

ABSTRACT

A medical device known as a trial neuro stimulator with a diagnostics module to determine whether the therapy lead is operational for delivering stimulation therapy to improve operation in areas such as reliability and patient comfort is disclosed. The trial neuro stimulator is typically used to test the efficacy of neuro stimulation before implanting an implantable neuro stimulator in a patient. The trial neuro stimulator has a processor, memory, system reset, telemetry module, recharge module, power management module, power source, therapy module, therapy measurement module, and diagnostics module. The diagnostics module can be a lead sensor, a software detector using therapy lead measurements from the therapy measurement module, or, a combination of both the lead sensor and software detector to detect whether the therapy lead is operational. A method for diagnosing whether a therapy lead is operational is also disclosed.

RELATED APPLICATION

The present application is a continuation of U.S. application Ser. No.09/596,220, filed Jun. 19, 2000, which issued as U.S. Pat. No. 6,687,538on Feb. 3, 2004, the entire content of which is incorporated herein byreference.

BACKGROUND OF THE INVENTION

This disclosure relates to a medical device and more specifically to aneuro stimulator that produces an electrical stimulation signal used toinfluence the human body.

The medical device industry produces a wide variety of electronic andmechanical devices for treating patient medical conditions. Dependingupon medical condition, medical devices can be surgically implanted orconnected externally to the patient receiving treatment. Clinicians usemedical devices alone or in combination with drug therapies and surgeryto treat patient medical conditions. For some medical conditions,medical devices provide the best, and sometimes the only, therapy torestore an individual to a more healthful condition and a fuller life.One type of medical device that can be used is an Implantable NeuroStimulator (INS)

An INS generates an electrical stimulation signal that is used toinfluence the human nervous system or organs. Electrical contactscarried on the distal end of a lead are placed at the desiredstimulation site such as the spine and the proximal end of the lead isconnected to the INS. The INS is then surgically implanted into anindividual such as into a subcutaneous pocket in the abdomen, pectoralregion, or upper buttocks area. The INS can be powered by an internalsource such as a battery, or by an external source such as a radiofrequency transmitter. A clinician programs the INS with a therapy usinga programmer. The therapy configures parameters of the stimulationsignal for the specific patient's therapy. An INS can be used to treatconditions such as pain, incontinence, movement disorders such asepilepsy and Parkinson's disease, and sleep apnea. Additional therapiesappear promising to treat a variety of physiological, psychological, andemotional conditions. Before an INS is implanted to deliver a therapy,an external screener that replicates some or all of the INS functions istypically connected to the patient to evaluate the efficacy of theproposed therapy.

When a screener is used to test the efficacy of a stimulation therapy,the screener including its leads should be fully operational tocorrectly assess the efficacy of the proposed stimulation therapy. Whenprevious screeners were operationally connected to a patient, theclinician would verify that the leads were operational. Once the patientleft the clinician's office the stimulation therapy efficacy could bereduced by stimulation energy not reaching the targeted site due toleads that have become inoperative through a nonconformance,disconnection, or open connection, and the patient might not becomeaware of the inoperative lead until the next visit with a clinician. Inother situations the leads may become temporarily inoperative which cansubject the patient to abrupt initiation and cessation of stimulationtherapy causing patient discomfort and unreliable indications ofefficacy. Unreliable efficacy testing data can result in some patientsnot receiving an INS when the therapy would have treated their medicalcondition, and other patients receiving an INS when the therapy wouldnot effectively treat their medical condition. An example of a screeneris shown in a brochure titled “Model 3625 Screener” available fromMedtronic, Inc., Minneapolis, Minn., and examples of some neurostimulation products and related components are shown and described in abrochure titled “Implantable Neurostimulation Systems” also availablefrom Medtronic, Inc.

For the foregoing reasons there is a need for a screener that candiagnose inoperative leads to improve operation in areas such asreliability, and patient comfort.

SUMMARY OF THE INVENTION

A trial neuro stimulator for delivery of stimulation therapy has a leaddiagnostic module coupled to a therapy module connector and iscoupleable to a therapy lead to improve operation in areas such asreliability and patient comfort. The lead diagnostic module isconfigured for determining whether the therapy lead is operational todeliver stimulation signals. The therapy module is operated according tothe therapy program to produce stimulation signals. The therapy programis contained in memory and executed by a processor coupled to memory.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an environment of a Trial Neuro Stimulator (TNS);

FIG. 2 shows a TNS with therapy lead embodiment;

FIG. 3 a shows a TNS embodiment;

FIG. 3 b shows another view of the TNS embodiment;

FIG. 3 c shows another TNS embodiment;

FIG. 4 shows an exploded view of the TNS embodiment;

FIG. 5 shows a TNS block diagram embodiment;

FIG. 6 shows a TNS basic operation flowchart embodiment;

FIG. 7 shows a therapy module block diagram embodiment;

FIG. 8 shows a therapy module operation flowchart embodiment;

FIG. 9 shows a therapy measurement block diagram embodiment;

FIG. 10 shows a therapy measurement operation flowchart embodiment;

FIG. 11 shows a TNS with lead diagnostics embodiment;

FIG. 12 shows a lead diagnostics module and related componentsembodiment;

FIG. 13 shows a lead diagnostics module operational flowchartembodiment;

FIG. 14 shows a lead diagnostics lead sensor and related componentsblock diagram embodiment;

FIG. 15 shows a lead diagnostic lead sensor operation flowchartembodiment;

FIG. 16 shows a lead diagnostics software detector and relatedcomponents block diagram embodiment;

FIG. 17 shows a lead diagnostics software detector operation flowchartembodiment; and

FIG. 18 shows a lead diagnostics operation flowchart embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows the general environment of a Trial Neuro Stimulator (TNS)20 medical device including a lead extension 22, and stimulation lead24, an Implantable Neuro Stimulator (INS) 26, a physician programmer 28,and a patient programmer 30. The stimulation lead 24 is one or moreinsulated electrical conductors with a connector 32 on the proximal endand electrical contacts 34 on the distal end. Some stimulation leads 24are designed to be inserted into a patient percutaneously, such as theModel 3487A Pisces-Quad® lead available from Medtronic, Inc. ofMinneapolis Minn., and some leads 24 are designed to be surgicallyimplanted, such as the Model 3993 Specify® lead also available fromMedtronic. Although the lead connector 32 can be connected directly tothe INS 26, typically the lead connector 32 is connected to a leadextension 22 which can be either temporary for use with a TNS 20 orpermanent for use with an INS 26. The lead extension 22, such as a Model7495 available from Medtronic, is then connected to the INS 26. The TNS20 functions similarly to the INS 26 but is not designed forimplantation. The TNS 20 is used to test the efficacy of stimulationtherapy for the patient before the INS 26 is surgically implanted. TheTNS 20 is typically connected to a screening cable 36 and the screeningcable 36 is connected to the percutaneous lead extension 22 which isconnected to the simulation lead 24. The physician programmer 28, alsoknown as a console programmer, uses telemetry to communicate with theimplanted INS 26, so a clinician can program and manage a patient'stherapy stored in the INS 26 and troubleshoot the patient's INS 26system. An example of a physician programmer 28 is a Model 7432 ConsoleProgrammer available from Medtronic. The patient programmer 30 also usestelemetry to communicate with the INS 26, so the patient can managesonic aspects of her therapy as defined by the clinician. An example ofa patient programmer 30 is a Model 7434 Itrel® 3 EZ Patient Programmeravailable from Medtronic.

Implantation of an Implantable Neuro Stimulator (INS) 26 typicallybegins with implantation of at least one stimulation lead 24 usuallywhile the patient is under a local anesthetic, The stimulation lead 24can either be percutaneously or surgically implanted. Once thestimulation lead 24 has been implanted and positioned, the stimulationlead's 24 distal end is typically anchored into position to minimizemovement of the stimulation lead 24 after implantation. The stimulationlead's 24 proximal end can be configured to connect to a lead extension22. The lead extension 22 can be a percutaneous lead extension with aproximal end that is external to the body and configured to connect toeither a screening cable 36 or directly to the Trial Neuro Stimulator(TNS) 20. The operational lead configuration is referred to as thetherapy lead 38 and includes a stimulation lead 24 and can, include alead extension 22, or a lead extension 22 and a screening cable 36.During the screening period the TNS 20 is programmed with a therapy andthe therapy is often modified to optimize the therapy for the patient.Once screening has been completed and efficacy has been established, thelead's 24 proximal end or the lead extension 22 proximal end isconnected to the INS 26. The INS 26 is programmed with a therapy andthen implanted in the body typically in a subcutaneous pocket at a siteselected after considering clinician and patient preferences. Theclinician periodically uses a console programmer 28 to communicate withthe implanted INS 26 to manage the patient therapy and collect INS 26data. The patient uses the patient programmer 30 to communicate with theimplanted INS 26 for purposes such as to make therapy adjustment thathave been programmed by the clinician, recharge the INS 26 power sourcewhen the INS 26 is configured for recharging, record diary entries aboutthe effectiveness of the therapy, and turning the INS 26 “on” and “off”.Both the console programmer 28 and patient programmer 30 can have anantenna locator that indicates when the telemetry head is alignedclosely enough with the implanted INS 26 for adequate telemetry.

FIG. 2 shows a Trial Neuro Stimulator (TNS) 20 with a screening cable36, lead extension 22, and a stimulation lead 24 having electricalcontacts 34. FIGS. 3 a and 3 b show views of a TNS 20 embodiment. FIG. 4shows an exploded view of a TNS 20 embodiment. FIG. 5 shows a blockdiagram of a TNS 20 embodiment. The TNS 20 generates a programmableelectrical stimulation signal that is used to evaluate the efficacy ofusing electrical stimulation to treat a patient condition. The TNS 20comprises a processor 40 with an oscillator 42, a calendar clock 44,memory 46, and system reset 48, a telemetry module 50, a recharge module52, a power source 54, a power management module 56, a therapy module58, a therapy measurement module 60, and a lead diagnostics module 62.In non-rechargeable versions of the TNS 20, the recharge module 52 canbe omitted. All components can be configured on one or more ApplicationSpecific Integrated Circuits (ASICs), or a combination of ASICs andcommercially available integrated circuits except the power source 54.Also, all components are connected to bi-directional data bus that isnon-multiplexed with separate address and data lines except theoscillator 42, the calendar clock 44, and the power source 54. Theprocessor 40 is a low power microcontroller such as a Motorola 68HC11synthesized core operating with a compatible instruction set. Theoscillator 42 operates at a frequency compatible with the processor 40,associated components, and energy constraints such as in the range from10.0 KHz to 4.0 MHz. The calendar clock 44 keeps track of the time sincea fixed date fox date/time stamping of events and for therapy controlsuch as circadian rhythm linked therapies. The memory 46 includes memory46 sufficient operation of the TNS 20 such as volatile Random AccessMemory (RAM) for example Static RAM, nonvolatile Read Only Memory (ROM),Electrically Eraseable Programmable Read Only Memory (EEPROM) forexample Flash EEPROM, and register arrays configured on ASICS. DirectMemory Access (DMA) is available to selected modules such as thetelemetry module 50, so the telemetry module 50 can request control ofthe data bus and write data directly to memory 46 bypassing theprocessor 40. The system reset 48 controls operation of ASICs andmodules during power-up and power-down of the TNS 20, so the ASICs andmodules registers can be loaded and brought on-line or off-line in astable condition. The TNS 20 can be configured in a variety of versionsby removing modules not necessary for the particular configuration andby adding additional components or modules. Primary cell,non-rechargeable, versions of the TNS 20 will not include some or all ofthe components in the recharge module 52. All components of the TNS 20are contained within or carried on a housing 64.

FIG. 6 shows a basic TNS 20 operation flowchart. Operation begins whenthe processor 40 receives data from either telemetry or from an internalsource in the TNS 20. The received data is then stored in a memory 46location. The data is processed by the processor 40 to identify the typeof data and can include further processing such as validating theintegrity of the data. After the data is processed, a decision is madewhether to take an action. If no action is required, the TNS 20 standsby to receive data. If an action is required, the action will involveone or more of the following modules or components: calendar clock 44,memory 46, telemetry 50, recharge 52, power management 56, therapy 58,and therapy measurement 60. An example of an action would be to modify aprogrammed therapy. After the action is taken, a decision is madewhether to prepare the action to be communicated, known as uplinked, toa patient programmer 30 or console programmer 28 through the telemetrymodule 50. If the action is uplinked, the action is recorded in thepatient programmer 30 or console programmer 28. If the action is notuplinked, the action is recorded internally within the TNS 20.

FIG. 7 shows a therapy module 58 block diagram. The therapy module 58generates a programmable stimulation signal 60 that is transmittedthrough one or more leads 24 to electrical contacts 34 implanted in thepatient. The therapy module 58 comprises a therapy controller 62, agenerator 64, a regulator module 66, and electrical contact switches 68.The therapy controller 62 can be a state machine having registers and atimer. The therapy controller 62 controls the generator 64 and regulatormodule 66 to create a stimulation signal 60. The generator 64 assemblescapacitors that have been charged by the power source 54 to generate awide variety of voltages or currents. The regulator module 66 includescurrent/voltage regulators that receive a therapy current or voltagefrom the generator controller 64 and shape the stimulation signal 60according to the therapy controller 62. The electrical contact switches68 are solid state switches such as Field Effect Transistor (FET)switches. The electrical contacts 34 are carried on the distal end of alead 24 and deliver the stimulation signal 60 to the body. Additionalswitches can be added to provide a stimulation signal 60 to additionalelectrical contacts 34. The therapy module 58 can deliver individualoutput pulses in the range from 0.0 Volts to 15.0 Volts into a rangefrom about 100 Ohms to 20.0 K Ohms impedance throughout the capabilitiesof its operating parameter range to any combination of anodes andcathodes of up to eighteen electrical contacts 34 for any givenstimulation signal 60.

FIG. 8 shows therapy module 58 operation with a flowchart. The therapybegins with the therapy controller 62 configuring the generator 64according to the therapy program to provide appropriate voltage to theregulator module 66. The therapy controller 62 also configures theregulator module 66 to produce the stimulation signal 60 according tothe therapy program. The therapy controller 62 also configures theelectrical contacts 34 to so the stimulation signal 60 is delivered tothe electrical contacts 34 specified by the therapy program. Thestimulation signal 60 is delivered to the patient. After the stimulationsignal 60 is delivered to the patient, most therapies include a timedelay for stimulation pulse recharge before the next stimulation signal60 is delivered.

FIG. 9 shows a therapy measurement module 60 block diagram. The therapymeasurement module 60 measures one or more therapy parameters at thetherapy module 58 to determine whether the therapy is appropriate. Thetherapy measurement module 60 includes a therapy voltage measurement 70,and a therapy current measurement 72. The therapy voltage measurementsand therapy current measurements are taken periodically to performtherapy calculations such as therapy lead 38 impedance. Morespecifically therapy lead 38 impedance is typically measured bymeasuring stimulation current and stimulation voltage, or stimulationcharge.

FIG. 10 shows a therapy measurement module 60 operation flowchart. Thetherapy measurement operation begins by processor 40 setting upparameters of the therapy measurement to be taken such as whichstimulation signal parameter to measure and at which electrical contactsto make the measurement. Before a therapy measurement is taken athreshold determination can be made whether a therapy measurement isneeded. When a therapy measurement is desired, the therapy is deliveredand then the therapy measurement is taken. The therapy measurement isreported to the processor 40 for action or storage in memory 46.Examples of some actions that might be take when the therapy measurementis reported include an adjustment to the therapy, notification that thetherapy lead is not fully operational or inoperative, and a diary entryin memory that can be evaluated by the clinician at a later time.

FIG. 11 shows a Trial Neuro Stimulator (INS) 20 with lead diagnosticsblock diagram embodiment, and FIG. 12 shows a TNS 20 with therapy leadembodiment. The TNS 20 with diagnostics for screening a patient toevaluate the efficacy of neuro stimulation comprises a processor 40,memory 46, a therapy module 58, and a lead diagnostics module 62. TheTNS 20 can also include additional components such as an annunciator.The processor 40 and memory 46 containing a therapy program are similarto those disclosed under the FIG. 4 discussion. The therapy program issimilar to that disclosed under the FIGS. 1, 7, and 8 discussion. Thetherapy module 58 is operated according to the therapy program toproduce stimulation signals 60. The therapy module 58 has a therapymodule connector 74 coupled to the lead diagnostic module 62 which iscoupleable to a therapy lead 38. The lead diagnostic module 62 isconfigured for determining whether the therapy lead 38 is operational todeliver stimulation signals 60. Lead diagnostics module 62 can alsodetect when the therapy lead 38 is not operationally connected to thetherapy module 58. The therapy lead 38 has a proximal end with a therapylead connector 76, and the therapy lead connector 76 is configured tocouple with the therapy module connector 74 and the lead diagnosticmodule 62. The therapy lead 38 includes a stimulation lead 24 and insome embodiments includes a lead extension 22 and in other embodimentsincludes both a lead extension 22 and a screening cable 36. The therapylead 38 has a proximal end with a therapy lead connector 76. The therapylead connector 76 is configured to couple with the therapy module 58 andthe lead diagnostics module 62. The therapy lead 38 can become not fullyoperational or inoperative for a wide variety of reasons such as whenthe screening cable 36 becomes electrically disconnected from thetherapy module connector 74, the screening cable 36 electricalconductors loose continuity, the lead extension 22 becomes electricallydisconnected from either the stimulation lead 24 or the screening cable36 or the TNS 20 depending upon embodiment, the extension lead 22electrical conductors loose continuity, the stimulation lead 24electrical conductors loose continuity, or corrosion degrades anelectrical connection in the therapy lead 38. The annunciator,annunciates when the therapy lead 38 in not operational to deliverstimulation signal.

FIG. 12 shows a lead diagnostics module 62 block diagram embodiment, andFIG. 13 shows a lead diagnostics operation flowchart embodiment. Thelead diagnostics module 62 is coupled to the therapy module connector 76and coupleable to a therapy lead 38. The lead diagnostics module 62senses whether the therapy lead 38 is operable to deliver stimulationsignals. If the therapy lead 38 is operable, the lead diagnostics 62periodically or continuously checks to determine if the therapy lead 38continues to be operational. If the diagnostics module 62 determinesthat the therapy lead 38 is not operational to deliver stimulationsignals 62, the therapy program can be modified to reduce stimulationshock when the therapy lead 38 becomes operational to deliverystimulation signals 60. Stimulation shock can be reduced by graduallyincreasing stimulation signal 60 parameters of the therapy program whenthe therapy lead 38 becomes operational. The lead diagnostics module 62can be configured in a variety of embodiments including as a lead sensor76 embodiment, a lead measurement embodiment, or a combination leadsensor and lead measurement embodiment.

FIG. 14 shows a lead sensor block diagram embodiment, and FIG. 15 showsa lead sensor flowchart embodiment. The lead sensor 75 can be configuredwith complimentary details in the therapy lead connector 76 and thetherapy module connector 74. The therapy lead connector 76 can have atleast one lead sensor detail that mates with at least one therapy moduledetail carried in the therapy module connector 74 to operate the leadsensor 75. As illustrated in FIG. 3 a, the lead sensor 75 detail can beconfigured as at least one lead connector pin 78 in the therapy leadconnector 76 and at least one therapy connector plug 80 configured toreceive the lead connector pin 78 in the therapy module connector 74 anddetect whether therapy lead connector 76 is operationally connected tothe therapy module connector 74. In one embodiment, as furtherillustrated in FIG. 3 a, the lead connector pin 78 can be configured toactuate a switch 82 carried in the trial neuro stimulator 20. In anotherembodiment the lead connector pin 78 can also be configured to completea circuit 83 carried in the therapy module connector 74 or, asillustrated in FIG. 3 c, the trial neuro stimulator 20. In anotherembodiment, the lead connector pin 78 can be magnetic and configured tooperate a magnetic switch carried in the therapy sensor.

The lead diagnostics module 62 can also be configured as a leadmeasurement embodiment.

FIG. 16 shows a lead measurement block diagram embodiment, and FIG. 17shows a lead measurement flowchart embodiment The lead diagnostic module62 includes a software detector 84 that receives therapy lead 38measurement data from a therapy measurement module.

The therapy lead 38 measurement data is used to determine whether thetherapy lead 38 is operational to deliver stimulation signals 60. Thetherapy measurement data is data that relates to therapy lead integritysuch as lead impedance. The lead impedance measurement can be comparedagainst predetermined data such as earlier lead impedance measurementsor a predetermined value to detect whether the therapy lead 38 isoperational. The lead measurement embodiment can also be used with thesensor embodiment discussed under FIG. 15. When the lead measurement andsensor are used together in an embodiment, the sensor 75 can provide aninput to the software detector 84, or the lead measurement embodimentand sensor embodiment can operate independently from one another. Leaddiagnostics can also be expressed as a method.

FIG. 18 shows a lead diagnostic method embodiment. The method ofdiagnosing whether a therapy lead is operationally connected to a trialneuro stimulator comprises the following elements. The therapy lead isconnected to a therapy connector. The integrity 88 of the connectionbetween the therapy lead 38 and the therapy connector 74 is sensed. Theintegrity of the connection between the therapy lead 38 and the therapyconnector 74 can be sensed with a lead sensor 75, the lead measurementsperformed by the therapy measurement module 60, or by a combination ofthe lead sensor 75 and therapy lead 38 measurements. A decision 90 ismade whether the integrity of the connection between the therapy lead 38and the therapy connector 74 is adequate. The decision 90 can be madedirectly by a lead sensor 75, or by a software detector 84, or by acombination of a lead sensor 75 and a software detector 84. If thedecision is that the therapy lead connection is inadequate, then theinadequate condition is annunciated 92 and the therapy can beterminated.

The inadequate condition can be directly annunciated to the patient witha transducer such as a visual, audible, tactile or combination of thesetransducers. The inadequate condition can also be annunciated directlyto INS 20 for one or more actions such as ceasing therapy, modifying thetherapy, logging the inadequate condition, and the like. Once theinadequate condition is corrected the therapy program can be modified togradually increase stimulation signal 60 parameters to the therapyprogram stimulation signal 60 parameter to reduce stimulation shock.Since nonconformance can be intermittent such that therapy lead onlybecomes inoperative when the patient makes a particular movement severaltimes a day, modifying the therapy to gradually increase stimulationsignal 60 parameter can greatly improve patient comfort and safety.

Thus, a Trial Neuro Stimulator (TNS) 20 with lead diagnostics isdisclosed to improve TNS operation in areas such as reliability andpatient comfort. One skilled in the art will appreciate that the presentinvention can be practiced with embodiments other than those disclosed.The disclosed embodiments are presented for purposes of illustration andnot limitation, and the present invention is limited only by the claimsthat follow.

1. A trial neuro stimulator with diagnostics for screening a patient toevaluate the efficacy of neuro stimulation comprising: a processor; amemory coupled to the processor containing a therapy program; a therapymodule operated according to the therapy program to produce stimulationsignals, the therapy module having a therapy module connector thatincludes at least one therapy connector plug; a therapy lead having adistal end for implantation in the patient and a proximal end thatincludes a therapy lead connector, the therapy lead connector configuredto couple with the therapy module connector outside of the patient andincluding at least one lead connector pin that is received by thetherapy connector plug; a lead diagnostic module configured fordetecting at least one of an operational disconnection of the therapylead from the therapy module, degradation of a conductor of the therapylead, or discontinuity of the conductor of the therapy lead, anddetermining that the therapy lead is not operational to deliverstimulation signals based on the detection; and a switch, wherein thelead connector pin actuates the switch, and the lead diagnostic moduledetects an operational disconnection of the therapy lead from thetherapy module by detecting whether the therapy lead connector isoperationally connected to the therapy module connector based onactuation of the switch, and wherein the trial neuro stimulator isconfigured for ambulatory operation.
 2. The trial neuro stimulator ofclaim 1, further comprising a therapy measurement module, wherein thelead diagnostic module includes a software detector that receivestherapy lead measurement data from the therapy measurement module anddetects the at least one of the operational disconnection of the therapylead from the therapy module, degradation of the conductor of thetherapy lead, or discontinuity of the conductor of the therapy lead bycomparing the therapy lead measurement data to predetermined data. 3.The trial neuro stimulator of claim 2, wherein the therapy measurementmodule is configured to measure a therapy lead impedance.
 4. The trialneuro stimulator of claim 1, further comprising an annunciator toannunciate when the at least one of the operational disconnection of thetherapy lead from the therapy module, degradation of the conductor ofthe therapy lead, or discontinuity of the conductor of the therapy leadis detected.
 5. The trial neuro stimulator of claim 1, wherein thetherapy lead comprises one of an implanted lead coupled to apercutaneous extension and a percutaneous lead.
 6. The trial neurostimulator of claim 1, wherein the therapy lead includes a screeningcable, and a proximal end of the screening cable includes the therapylead connector.
 7. A trial neuro stimulator with diagnostics forscreening a patient to evaluate the efficacy of neuro stimulationcomprising: a processor; a memory coupled to the processor containing atherapy program; a therapy module operated according to the therapyprogram to produce stimulation signals, the therapy module having atherapy module connector that includes at least one therapy connectorplug; a therapy lead having a distal end for implantation in the patientand a proximal end that includes a therapy lead connector, the therapylead connector configured to couple with the therapy module connectoroutside of the patient and including at least one lead connector pinthat is received by the therapy connector plug; a lead diagnostic moduleconfigured for determining whether the therapy lead is operational todeliver stimulation signals; and a switch, wherein the lead connectorpin actuates the switch and the lead diagnostic module determineswhether the therapy lead is not operationally connected to the therapymodule by detecting whether the therapy lead connector is operationallyconnected to the therapy module connector based on actuation of theswitch.
 8. The trial neuro stimulator of claim 7, further comprising atherapy measurement module, wherein the lead diagnostic module includesa software detector that receives therapy lead measurement data from thetherapy measurement module, compares the therapy lead measurement datato predetermined data, and determines whether the therapy lead is notoperationally connected to the therapy module based on the comparison.9. A trial neuro stimulator with diagnostics for screening a patient toevaluate the efficacy of neuro stimulation comprising: a processor; amemory coupled to the processor containing a therapy program; a therapymodule operated according to the therapy program to produce stimulationsignals, the therapy module having a therapy module connector thatincludes at least one therapy connector plug; a therapy lead having adistal end for implantation in the patient and a proximal end thatincludes a therapy lead connector, the therapy lead connector configuredto couple with the therapy module connector outside of the patient andincluding at least one lead connector pin that is received by thetherapy connector plug; a lead diagnostic module configured fordetecting at least one of an operational disconnection of the therapylead from the therapy module, degradation of a conductor of the therapylead, or discontinuity of the conductor of the therapy lead, anddetermining that the therapy lead is not operational to deliverstimulation signals based on the detection; and a circuit, wherein thelead connector pin completes the circuit, and the lead diagnostic moduledetects an operational disconnection of the therapy lead from thetherapy module by determining whether the therapy lead connector isoperationally connected to the therapy module connector based oncompletion of the circuit, and wherein the trial neuro stimulator isconfigured for ambulatory operation.
 10. A trial neuro stimulator withdiagnostics for screening a patient to evaluate the efficacy of neurostimulation comprising: a processor; a memory coupled to the processorcontaining a therapy program; a therapy module operated according to thetherapy program to produce stimulation signals, the therapy modulehaving a therapy module connector that includes at least one therapyconnector plug; a therapy lead having a distal end for implantation inthe patient and a proximal end that includes a therapy lead connector,the therapy lead connector configured to couple with the therapy moduleconnector outside of the patient and including at least one leadconnector pin that is received by the therapy connector plug; a leaddiagnostic module configured for determining whether the therapy lead isoperational to deliver stimulation signals; and a circuit, wherein thelead connector pin completes the circuit and the lead diagnostic moduledetermines whether the therapy lead is not operationally connected tothe therapy module by detecting whether the therapy lead connector isoperationally connected to the therapy module connector based oncompletion of the circuit.
 11. A medical device comprising: a processor;a memory coupled to the processor containing a therapy program; atherapy module operated according to the therapy program to producestimulation signals, the therapy module having a therapy moduleconnector that includes at least one therapy connector plug; a therapylead having a distal end for implantation in the patient and a proximalend that includes a therapy lead connector, the therapy lead connectorconfigured to couple with the therapy module connector outside of thepatient and including at least one lead connector pin that is receivedby the therapy connector plug; a lead diagnostic module configured fordetecting at least one of an operational disconnection of the therapylead from the therapy module, degradation of a conductor of the therapylead, or discontinuity of the conductor of the therapy lead, anddetermining that the therapy lead is not operational to deliverstimulation signals based on the detection; and a switch, wherein thelead connector pin actuates the switch and the lead diagnostic moduledetects an operational disconnection of the therapy lead from thetherapy module by detecting whether the therapy lead connector isoperationally connected to the therapy module connector based onactuation of the switch.
 12. A medical device comprising: a processor; amemory coupled to the processor containing a therapy program; a therapymodule operated according to the therapy program to produce stimulationsignals, the therapy module having a therapy module connector thatincludes at least one therapy connector plug; a therapy lead having adistal end for implantation in the patient and a proximal end thatincludes a therapy lead connector, the therapy lead connector configuredto couple with the therapy module connector outside of the patient andincluding at least one lead connector pin that is received by thetherapy connector plug; a lead diagnostic module configured fordetecting at least one of an operational disconnection of the therapylead from the therapy module, degradation of a conductor of the therapylead, or discontinuity of the conductor of the therapy lead, anddetermining that the therapy lead is not operational to deliverstimulation signals based on the detection; and a circuit, wherein thelead connector pin completes the circuit and the lead diagnostic moduledetects an operational disconnection of the therapy lead from thetherapy module by determining whether the therapy lead connector isoperationally connected to the therapy module connector based oncompletion of the circuit.